Check Engine Light (CEL) – What Can Cause It To Come On

Check Engine Light (CEL) - What Can Cause It To Come On
Check Engine Light (CEL) - What Can Cause It To Come On

Seeing a check engine light (CEL); is one of the most frustrating and confusing factors, of owning a vehicle.

So, the check engine light (CEL), is just a light, with no information; telling you that there is a problem, somewhere in your vehicle.

Does it mean you have time to get it to a mechanic; when you have time or will you end up towing your vehicle back home, the next time you drive?

However, as ambiguous as a check engine light (CEL) may be; your vehicle’s onboard diagnostic system, is essential to keeping the engine running efficiently.

So, flashing or blinking warning lights or a check engine light (CEL); should be addressed, as soon as possible. Because, warning lights on the dashboard are simply that, warnings. Consequently, if one of the lights stays on after you start your vehicle; you could potentially have a problem. Therefore, you should have your vehicle inspected, for needed repairs.

Flashing Or Blinking Dash Warning Lights
Flashing Or Blinking Dash Warning Lights

The lights may come on, when the onboard diagnostics (OBD) system; finds a problem in the electronic control system, that it can’t correct. Consequently, there are two systems, OBD-I and the upgrade to OBD-II

The (OBD) System Could Turn On:

  • A check engine light (CEL)
  • It could say “service engine soon”
  • Possibly “check powertrain”
  • The light may be nothing more, than a picture of an engine. Also, known as the International Check Engine Symbol; perhaps with the word “Check.”

In addition, to turning on the light; the computer stores a “trouble code” in its memory; that identifies the source of the problem; such as a malfunctioning sensor or a misfiring engine.

So, an electronic scan tool or a diagnostic computer, can read the code. As a result, this is usually standard equipment, in auto repair shops.

Electronic Scan Tool
Electronic Scan Tool

Furthermore, there are also a number of relatively inexpensive code readers; that are designed for the (DIY).

NOTE: Almost, all parts suppliers will read your code for free !

Some Common Reasons, The Check Engine Light (CEL) has turned on include:

  • Loose or missing gas cap.
  • Worn out, sparks plugs or wires.
  • Electronic control module failure.
  • Defective distributor or coil packs.
  • Emissions control fault; such as the oxygen (O2)sensor.
  • Fuel quality issue.
Check Engine Light Possible Causes
Check Engine Light Possible Causes

Finally, The Top Check Engine Light Car Repairs:

  1. Replacing oxygen (O2) sensor(s), Failing catalytic converter(s)
  2. Faulty ignition coil(s) and spark plugs
  3. Loose fuel or gas cap
  4. Replacing thermostat
  5. Faulty ignition coil(s)
  6. Replacing mass air flow (MAF) sensor
  7. Bad spark plugs and spark plug wires
  8. Malfunctioning, evaporative emissions (EVAP) purge control valve
  9. Replacing evaporative emissions (EVAP) purge solenoid


So, if one of the lights stays on, after you start your vehicle; you could potentially have a engine problem and should have your vehicle; inspected for needed repairs. Although it’s likely that the problem will be minor; it’s always best to get it checked.

Before, it leads to a more disastrous accident. Because, this has been known to happen! So, make sure that any problems with your vehicle are checked; before embarking on any long drives.

Thank You !